Users in high volume print environments continue to have an increasing demand for reliable and more immediate output. Generally, this need is handled by printer pooling, where the user sends the print job to a logical printer which is associated with multiple physical printers. The logical printer implements a printer selection process that selects one or more of the physical printers that are sent the print job.
Referring to FIG. 1A, a printer selection process 14 is based on printer availability. In one example, printers A-C are classified as either in a ready, busy or error state. A print job for document 12 is routed according to the afore-mentioned preference order. For example, the Ricoh Smart Monitor® implements this form of availability using a custom port monitor and querying the device to determine device status.
The Microsoft Windows NT/2K and XP® operating systems implement a similar form of availability using a port monitor. For Windows NT/2K® printer pooling, the printers are classified as ready or busy by querying a local spooler, and the print job is routed according to the afore-mentioned preference order. In Windows XP® printer pooling, the printers are classified by querying the device using Simple Network Management Protocol (SNMP), and the print job is routed according to the afore-mentioned preference order.
Printer pooling by availability may also be used to restart a failed print job on an alternate printer, such as by having a print subsystem component (e.g., print processor, print spooler or port monitor) monitor the completion of a print job after it has been routed to a printer. If the print job fails to complete without error, the print subsystem component restarts the job on the next available printer in the pool.
In another example of availability, an estimate is made when each printer in the pool will become available when all the printers are currently busy printing. The printer that is estimated to be the first to become available is selected as the most available printer. In another example of availability, an idle printer is further distinguished between power save mode and powered up. A printer in power save mode needs additional time to warm up and therefore is less available than a powered up printer.
In FIG. 1B, the printer selection process 14 is based on the load on printers A-C. In one example, the load on each printer A-C is quantified and the print job is routed to the printer with the least load. For example, the number of jobs currently printing/pending on the printers may be used as a load measurement and saturation level.
FIG. 1C shows another scheme where the printer selection process 14 is based on performance of printers A-C. In one example, the performance of each printer A-C is determined as the printer's rated pages per minute (ppm), and a print job for document 12 is routed to the printer A-C with the highest rated performance.
FIG. 1D shows a scheme where the printer selection process 14 for printing document 12 is based partially on locality of printers A-C. In one example, the location of the printers A-C relative to the device conducting the printer selection process 14 is determined. The printer selection process 14 may then route the print job by ranking printers according to how well they match the print preferences such as speed, quality, Black and White (BW) vs. color, Page Description Language (PDL) and distance from the issuer.
FIG. 1E shows another technique where the printer selection process 14 for printing document 12 is based on power consumption of printers A-C. In one example, the power consumption of each combination of devices (e.g., printer and finisher) required to complete the print job is determined. The print job is then routed to the combination that consumes the least amount of power.
FIG. 1F shows another scheme where the printer selection process 14 for document 12 is based on consumable availability. In this example, the amount of consumables is determined for items such as paper stock and toner. The print job is then routed to the printer A-C with sufficient consumables to process the print job.